The application generally relates to a system and method for a non-contact rapid reader system for reflective particle tags, or labels, (RPT) applied to containers and other articles for monitoring. Containment and surveillance measures are critical to any verification regime in order to monitor certain highly secured and restricted activities, e.g., transportation of nuclear fuel and its components across international borders; to detect undeclared activities related to national security and restricted activities; to verify the integrity of equipment or items; to reduce inspector burden; and to maintain a chain of custody between inspections.
A tag is an exemplary measure used to establish the identity of an accountable item and maintain the chain of custody for the respective item. Tags must also provide evidence of tampering of the tag itself, e.g., counterfeiting or substitution, and if applied in an appropriate manner, e.g., across a seam of a container, a tag may also provide evidence of tampering with the item. Continual improvement of measures such as tags is required to counteract technical advances of adversaries which could render C/S equipment obsolete with a single technical advancement. Furthermore, new architectures are required to respond to changing requirements arising from the introduction of new procedures or approaches, and it is often desirable to incorporate technological advances that provide efficiency gains or allow deployment in new application spaces.
The RPT was developed to identify items that must be accounted for under international treaties. In most instances the tag, or RPT, is composed of an article with unique optical characteristics, e.g., specular hematite particles randomly dispersed in a clear, adhesive polymer matrix.
Reflective particle tags (RPT) derive their unique identities through utilization of thousands of microscopic reflective elements randomly suspended in a clear adhesive matrix. For verification of the authenticity, an illumination/imaging system is used to “read” information about precise positions and orientations of faceted particles. SNL developed the original Reflective Particle Tag (RPT) system, comprising a tag and an imager, in the 1990's to identify treaty-accountable items. Since then, the RPT system has evolved with advances in computing, imaging, and materials, and is considered a robust, low-cost, hard-to-counterfeit passive tagging system for treaty verification. However, a limitation of the current system is the need to mechanically dock the reader with the tag, which prevents its use in many situations. This paper discusses R&D at SNL to develop a non-contact handheld imaging system that will allow RPT system use in new scenarios and allows automation.
The RPT architecture is effective for detection of counterfeiting and removal of tags. Furthermore, RPTs require no power source, and maintain stability through temperature extremes, rough handling, and years of service. Such attributes make RPTs suitable for applications with strict facility acceptance requirements and for deployments in which a semi-permanent tag should be attached to an item to be monitored. However, the current RPT system referred to as a contact-type RPT system, suffers from certain deficiencies that limit potential applications. The contact-type RPT derives its security capability through precise alignment between a reader and the RPT, and relies on tightly collimated illumination beams and a small aperture to allow only facets oriented within approximately one degree of the optimal direction to contribute to the recorded image. In order to achieve such precision, the reader must be placed in contact with the flat frame in which the RPT is mounted or attached. However, such physical contact may be undesirable or not permitted by a facility owner. In addition, the use of a flat frame is incompatible where tags must be affixed to complex geometries and curved surfaces.
What is needed is a system and/or method for rapidly testing and evaluating optical designs of computational and compressive imaging sensing (CS) systems. The term compressive sensing (CS) is used interchangeably with computational imaging, for purposes of this disclosure.